Fuel tank cap for a fuel tank

ABSTRACT

A fuel tank cap for a fuel tank of an engine. The fuel tank cap includes a fuel cap cover, a housing having a side wall, a bottom wall, and a receptacle, a fuel vapor adsorption material positioned within the receptacle, an inlet disposed near the bottom wall and configured to provide fluid communication with a fuel tank vapor space, an outlet disposed near the bottom wall and configured to provide fluid communication with the atmosphere, an internal wall adjacent the bottom wall and disposed between the inlet and the outlet, and at least one aperture configured to permit fuel vapor to flow in a vapor flow path from one side of the internal wall to the other side of the internal wall.

BACKGROUND

The present invention relates to a fuel tank cap for capturingevaporative emissions from fuel tanks or other engine components.

Internal combustion engines are often used to power small equipment suchas lawnmowers, tillers, snow throwers, lawn tractors and the like. Thefuel system includes a tank, in which fuel is stored for use. Generally,the volatility of the fuel allows a portion of the fuel to evaporate andmix with air within the tank. Changes in temperature, such as thosebetween evening and daytime, as well as sloshing during use can cause anincrease or a decrease in the amount of fuel vapor in the tank as wellas an increase or a decrease in the pressure within the tank.

To deal with the fuel vapor, the fuel tank cap often includes afiltering element. The filtering element filters the fuel vapor from theair to substantially reduce or eliminate any fuel vapor emissions fromthe fuel system.

SUMMARY

In one embodiment, the invention provides a fuel tank cap for a fueltank of an engine. The fuel tank cap includes a fuel cap cover, ahousing having a side wall, a bottom wall, and a receptacle, a fuelvapor adsorption material positioned within the receptacle, an inletdisposed near the bottom wall and configured to provide fluidcommunication with a fuel tank vapor space, an outlet disposed near thebottom wall and configured to provide fluid communication with theatmosphere, an internal wall adjacent the bottom wall and disposedbetween the inlet and the outlet, and at least one aperture configuredto permit fuel vapor to flow in a vapor flow path from one side of theinternal wall to the other side of the internal wall.

In another embodiment, the invention provides a fuel tank cap for a fueltank of an engine. The fuel tank cap includes a fuel cap cover, ahousing having a side wall, a bottom wall, and a receptacle, a fuelvapor adsorption material positioned within the receptacle, a fuel vaporinlet disposed near the bottom wall and configured to provide fluidcommunication with a fuel tank vapor space, an outlet disposed near thebottom wall and configured to provide fluid communication with theatmosphere, an internal wall adjacent the bottom wall and disposedbetween the inlet and the outlet, the internal wall creating a firstregion on one side of the internal wall and a second region on an otherside of the internal wall, and at least one aperture configured topermit fuel vapor to flow in a fuel vapor flow path from the firstregion to the second region.

In another embodiment, the invention provides a fuel tank cap for a fueltank of an engine. The fuel tank cap includes a housing having a bottomwall, a receptacle formed in the housing, an inlet disposed near thebottom wall and configured to provide fluid communication with a fueltank vapor space, an outlet disposed near the bottom wall and configuredto provide fluid communication with the atmosphere, a fuel vaporadsorption material positioned within the receptacle, an internal wallextending into the receptacle and disposed between the inlet and theoutlet, and at least one aperture configured to permit fuel vapor toflow from one side of the internal wall to the other side of theinternal wall. The internal wall is configured to direct fuel vaporthrough the longest volume of the fuel vapor adsorption material in afuel vapor flow path.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an engine including the fuel tank cap ofthe present invention.

FIG. 2 is an exploded perspective view of one embodiment of the fueltank cap of present invention.

FIG. 3 is a cross-sectional view of the fuel tank cap of FIG. 2.

FIG. 4 is a top perspective view of the fuel tank cap housing of FIG. 2.

FIG. 5 is a bottom perspective view of the fuel tank cap housing of FIG.2.

FIG. 6 is a top view of the fuel tank cap housing of FIG. 2.

FIG. 7 is a bottom view of the fuel tank cap housing of FIG. 2

FIG. 8 is an exploded perspective view of another embodiment of the fueltank cap of the present invention.

FIG. 9 is a cross-sectional view of the fuel tank cap of FIG. 8.

FIG. 10 is a top perspective view of the fuel tank cap housing of FIG.8.

FIG. 11 is a bottom perspective view of the fuel tank cap housing ofFIG. 8.

FIG. 12 is a top view of the fuel tank cap housing of FIG. 8.

FIG. 13 is a bottom view of the fuel tank cap housing of FIG. 8.

FIG. 14 is an exploded perspective view of another embodiment of thefuel tank cap of the present invention.

FIG. 15 is a top view of the fuel tank cap housing of FIG. 14.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways. Also, it is to be understood thatthe phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items. Unless specified or limited otherwise, theterms “mounted,” “connected,” “supported,” and “coupled” and variationsthereof are used broadly and encompass both direct and indirectmountings, connections, supports, and couplings. Further, “connected”and “coupled” are not restricted to physical or mechanical connectionsor couplings.

With reference to FIG. 1, an engine assembly 10 is illustrated. Toproperly operate the engine assembly 10, the engine assembly 10 includesa fuel tank 14, an air-fuel mixing device 11 and an air cleaner assembly13. Generally, the air-fuel mixing device 11 includes a carburetor, butit could also be a throttle body or other component of a fuel injectionsystem. The engine is similar to engines of a type that are often usedto power outdoor power equipment such as lawnmowers, garden tractors,snow throwers, tillers, pressure washers, generators, and the like.

Typically, the fuel tank 14 is sized based on the size of the engine andthe task to be performed by the device to which the engine and the fueltank are attached. Thus, a variety of fuel tank sizes are available. Asone of ordinary skill in the art will realize, several fuel tanks ofdifferent sizes can be used with engines. As such, the inventiondescribed herein should not be limited to use with fuel tanks sized asdescribed herein. Rather, the invention is applicable to different fueltanks in addition to those discussed. However, it should be understoodthat embodiments of the invention using fuel vapor adsorption materialmay be limited practically to engines using smaller fuel tanks, due tothe practical size limitations of the fuel vapor adsorption material forlarge fuel tanks, such that as the size of the fuel tank increases, thesize of the fuel vapor adsorption material increases accordingly. Thefuel tank 14 can be formed by a plurality of materials, including, butnot limited to, plastic, metal, composite, and the like. Manufacturingprocesses available to form the fuel tank include, but are not limitedto vacuum-forming, roto-molding, blow-molding, injection molding and thelike.

As shown in FIGS. 3 and 9, the fuel tank 14 further includes a fuel tankreservoir 18. The fuel tank reservoir 18 is integrally-formed with thetop portion of the fuel tank 14. Fuel 22 is retained in the fuel tank14, and fuel vapor 26 exists above the fuel 22 in the fuel tank 14 inthe fuel tank vapor space 30.

FIGS. 2 through 7 illustrate one embodiment of the fuel cap 34 of thepresent invention. FIG. 2 shows an exploded view of the fuel cap 34. Thefuel cap 34 includes a housing 38, an inlet 42, an outlet 46, aplurality of screens 50, fuel vapor adsorption material 54, acompression foam 58, a receptacle cover 62, a sealing gasket 64, atether 66, and a cap cover 70. As shown in FIG. 3, the fuel tank caphousing 38 is coupled with the filler neck 74 of the fuel tank 14 viathreads 39. However, in other embodiments, the fuel tank cap may have asnap-on configuration, push-on connection or similar connection. Gasket64 creates a fluid tight seal between the fuel tank housing 38 andfiller neck 74. The gasket 64 is configured to allow for compression fitwith the housing 38 and fluid access to the inlet 42.

As shown in FIGS. 2 through 7, the housing 38 has a side wall 78 and abase wall 82. The housing 38 is formed of materials such as acetyl,nylon, polypropylene, and like material. The housing 38 is preferably,among other things, a fuel-resistant, low resitivity, impact resistantmaterial. The inlet 42 is substantially positioned on the base wall 82and configured to provide fluid communication with the fuel tank vaporspace 30 (see FIG. 5). The outlet 46 is positioned on the base wall 82and configured to provide fluid communication with the atmosphere (seeFIG. 5). Screens 50 are positioned on a receptacle side of both theinlet 42 and outlet 46 to prevent the fuel vapor adsorption material 54from interfering with either of the inlet 42 or the outlet 46. Thescreens 50 are open-mesh and sized based on the carbon pellet size ofthe fuel vapor adsorption material 54. In other embodiments, the screenscan be any shape to match the size and shape of the inlet and theoutlet. The inlet 42 and outlet 46 both include at least one stand-off90 configured to keep the screens 50 in position and to protect theinlet 42 and outlet 46 from any compressive forces applied to thesystem. The fuel vapor adsorption material 54 is retained in thereceptacle 86 of the housing 38. In the illustrated embodiment of FIGS.2 and 3, the fuel vapor adsorption material 54 is carbon. In otherembodiments, the fuel vapor adsorption material can be anotheradsorption material capable of adsorbing fuel vapor.

The compression foam 58 is positioned adjacent the fuel vapor adsorptionmaterial 54 and retains the fuel vapor adsorption material 54 in thereceptacle 86. The compression foam 58 substantially compresses the fuelvapor adsorption material 54 along all axes. The compression foam 58provides abrasion resistance so that the fuel vapor adsorption material54 does not degrade by rubbing against itself or a hard surface.Furthermore, the compression foam 58 creates a seal over the receptacle86 to prevent fuel vapor from bypassing the vapor adsorption material54. The compression foam 58 is a low durometer, closed-cell elastomer.In other embodiments, the compression foam can be other types of foam,elastomeric material, or rubber material.

The receptacle cover 62 is positioned adjacent the compression foam 58and retains the compression foam 58 in the receptacle 86. The receptaclecover 62 is coupled to the fuel cap housing 38 with a material weld. Inother embodiments, alternative joining methods may be used, includingbut not limited to, gluing or snap fits. The tether 66 is adapted toallow the fuel tank cap 34 to be removably attached to the filler neck74 extending from the fuel tank 14, and attached so that the fuel tankcap 34 remains coupled to the fuel tank 14 to prevent loss of the fueltank cap 34 when it is removed from the filler neck 74 of the fuel tank14 during refueling. The fuel tank cap cover 70 is configured to bepositioned over the fuel cap housing 38. As shown in FIG. 3, the fueltank cap cover 70 is retained on the cap housing 38 by interlocking ribs71 and grooves 72. The cap housing 38 includes protrusions 94 extendingfrom the cap housing 38 and configured to provide a ratchet function(see FIG. 7). By rotating the fuel tank cap cover 70 at a predefinedtorque, the fuel tank cap cover 70 will engage the cap housing 38 byinterlocking with the protrusions 94 on the cap housing 38. Onceengaged, the fuel tank cap cover 70 and the cap housing 38 will resistmovement in the opposite direction, thereby preventing the fuel tank capcover 70 from being over-tightened.

The fuel cap 34 can further include an optional mounting device orapparatus 114 for any additional apparatus to be coupled to the fuel cap34. By way of example only, the additional apparatus may include a fueladditive capsule 116 (see FIG. 3), containing fuel stabilizer, asdescribed and illustrated in detail in U.S. Pat. No. 6,942,124 and U.S.Pat. No. 6,981,532, which are incorporated herein by reference. If afuel stabilizer capsule is included in mounting apparatus 114, thecapsule 116 is designed to automatically drip a small quantity of a fuelstabilizer liquid into the fuel tank 14; see U.S. Pat. Nos. 6,942,124and 6,981,532. A point or protrusion (not shown) in the mountingapparatus 114 creates a vent hole in the top of the fuel stabilizercapsule, as disclosed in U.S. Pat. Nos. 6,942,124 and 6,981,532. Asuitable fuel stabilizer capsule for use with the present invention issold by Briggs and Stratton Corporation under the trademark FRESH START.Vents 118 formed in the mounting apparatus 114 allow venting of the fueladditive capsule. Each of the fuel cap embodiments disclosed herein mayinclude the optional mounting device 114 and/or a fuel capsule 116disposed in the mounting device.

As shown in FIGS. 2 through 7, the housing 38 further includes areceptacle 86 configured to retain the fuel vapor adsorption material54. The receptacle 86 is divided by a plurality of internal walls 98.The internal walls 98 are integrally formed with the base wall 82 andthe side wall 78 of the housing 38. The internal walls 98 providepartitioned regions 102 a, 102 b, and 102 c within the receptacle 86 anddefine a general flow path 106 through the partitioned regions 102 a,102 b, and 102 c for fuel vapor 26 from the fuel tank 14.

Apertures or slits 110 are formed within the internal walls 98 andfurther define the general flow path 106 through the partitioned regions102 a, 102 b, and 102 c. As shown in FIGS. 2, 4, and 6, the internalwalls 98 are positioned to form a substantially “Y” shape. The inlet 42and outlet 46 are disposed within different partitioned regions 102 aand 102 c, respectively, in order to provide a general flow path 106through the longest volume at the center of the fuel vapor adsorptionmaterial 54.

As shown in FIGS. 4 and 6, the general flow path 106 extends from theinlet 42 through the fuel vapor adsorption material 54 and to the outlet46 in a substantially circular flow path 106. The general flow path 106is directed through the apertures 110 in the internal walls 98. Theapertures 110 are positioned to increase adsorption efficiency bydirecting the flow path generally through the center of the fuel vaporadsorption material and away from the side wall 78. However, in someembodiments, the fuel vapor 26 may also diffuse from the general flowpath 106 to the side wall 78 and the internal walls 98 in order toutilize more of the fuel vapor adsorption material 54.

In operation and as shown in FIGS. 3 and 4, when the engine is at rest,fuel vapor 26 is emitted from the fuel tank 14 and enters the fuel caphousing 38 through the inlet 42. The fuel vapor 26 follows the generalfuel vapor flow path 106 to the outlet 46. At the outlet 46, the fluidflow is substantially fuel vapor free and exits to the atmospherebecause the fuel vapor 26 is substantially retained in the fuel vaporadsorption material 54. The fuel vapor adsorption material 54 can bepurged of the fuel vapor 26 by reversing the general flow path such thatambient air enters the cap housing through the outlet and proceeds alongthe general flow path to the inlet as a result of a reduction in fueltank pressure. Fuel tank pressure reduction may result from conditions,for example, but not limited to natural effects, such as ambienttemperature changes, or engine effects, such as fuel consumption orintake vacuum. The air, now entrained with fuel vapor, can re-enter thefuel tank vapor space through the inlet, thereby effectively purging thefuel vapor adsorption material of the fuel vapor.

FIGS. 8 through 13 show an alternate embodiment of the fuel tank cap 234according to the present invention. The fuel tank cap 234 shown in FIGS.8 through 13 includes similar structure to the fuel tank cap 34illustrated in FIGS. 2 through 7 described above; therefore, similarcomponents are identified by the same reference numerals, plus “200”.The housing 238 has a side wall 278, a base wall 282, and a receptacle286. More specifically, as shown in FIGS. 8, 10, and 12, the internalwalls 298 are positioned within housing 238 to form a substantially “X”or cross shape. Apertures or slits 210 are formed within the internalwalls 298 and further define the general flow path 206 through thepartitioned regions 202 a, 202 b, 202 c, and 202 d. The inlet 42 andoutlet 46 are disposed within different partitioned regions 202 a and202 d, respectively, in order to provide a general flow path 206 thatwill provide for fuel vapor path flow 206 along the center, or longestpart of the fuel vapor adsorption media 254.

FIGS. 14 and 15 show an alternate embodiment of the fuel tank cap 334according to the present invention. The fuel tank cap 334 shown in FIGS.14 and 15 includes similar structure to the fuel tank cap 34 illustratedin FIGS. 2 through 7 described above; therefore, similar components areidentified by the same reference numerals, plus “300”. The housing 338has a side wall 378, a base wall 382, and a receptacle 386. Morespecifically, an internal wall 398 is positioned within housing 338between the inlet 342 and the outlet 346 to create partitioned regions302 a and 302 b. Screens 350 are positioned on receptacle side 386 ofboth inlet 342 and outlet 346. An aperture or slit 310 defines a generalflow path 306 through partitioned regions 302 a, 302 b. The inlet 342and outlet 346 are disposed within different partitioned regions 302 aand 302 b, respectively, in order to provide a general flow path 306that will provide for fuel vapor path flow 306 along the center, orlongest part of the fuel vapor adsorption media 354. The fuel vapor flowpath 306 is substantially “U” or circular shaped.

In the illustrated embodiments, the fuel vapor flow path configurationscan increase the filtering efficiency of the fuel tank cap. Morespecifically, the Y-shape and X-shape configurations (FIGS. 2 through 7and FIGS. 8 through 13, respectively) of the fuel tank cap are expectedto increase the filtering efficiency of the fuel tank caps 34 and 234 byapproximately, twenty percent over the embodiment shown in FIGS. 14 and15. The configuration of the internal walls essentially forces the fuelvapor flow path to extend throughout the fuel vapor adsorption material.The efficiency of fuel vapor adsorption is increased by keeping the fuelvapor flow path centralized to the volume of fuel vapor adsorptionmaterial. Accordingly, the volume of the fuel vapor adsorption materialis substantially equal on all sides of the fuel vapor flow path. Bykeeping the flow path centralized and away from the side wall of thehousing in the first and second embodiments, fuel vapor adsorption isincreased. The extended flow path through the fuel vapor adsorptionmaterial also increases the surface area of contact between the fuelvapor and the fuel vapor adsorption material. Accordingly, the extendedpath allows for substantially all of the fuel vapor to be adsorbed bythe fuel vapor adsorption material such that substantially fuel vaporfree air will be emitted to the atmosphere.

Various features and advantages of the invention are set forth in thefollowing claims.

1. A fuel tank cap that is removably coupled to a fuel tank of anengine, the fuel tank cap comprising: a fuel cap cover; a housing havinga side wall, a bottom wall, and a receptacle; a fuel vapor adsorptionmaterial positioned within the receptacle; an inlet disposed near thebottom wall and configured to provide fluid communication with a fueltank vapor space; an outlet disposed near the bottom wall and configuredto provide fluid communication with the atmosphere; a radially extendinginternal wall adjacent the bottom wall, the inlet and the outlet beingdisposed on opposite sides of the internal wall; and at least oneaperture configured to permit fuel vapor to flow in a vapor flow pathfrom one side of the internal wall to the other side of the internalwall.
 2. The fuel tank cap of claim 1, wherein the fuel vapor adsorptionmaterial includes activated carbon.
 3. The fuel tank cap of claim 1,wherein the vapor flow path is substantially circular.
 4. The fuel tankcap of claim 1, wherein the internal wall is a first internal wall, andwherein the fuel tank cap further includes at least two additionalradially extending internal walls adjacent the bottom wall andcontiguous with the first internal wall.
 5. The fuel tank cap of claim4, wherein each of at least two additional radially extending internalwalls has an aperture configured to permit passage of fuel vapor throughthe respective internal wall.
 6. The fuel tank cap of claim 5, whereinthe at least two additional radially extending internal walls includesat least three radially extending internal walls, and wherein acombination of the first internal wall and the at least three additionalradially extending internal walls has a substantially X-shapedconfiguration.
 7. The fuel tank cap of claim 5, wherein a combination ofthe first internal wall and the at least two additional radiallyextending internal walls has a substantially Y-shaped configuration. 8.The fuel tank cap of claim 1, wherein the internal wall extends from thebottom wall.
 9. The fuel tank cap of claim 1, wherein the inlet isdisposed in the bottom wall, and wherein the outlet is disposed in oneof the bottom wall and the side wall.
 10. The fuel tank cap of claim 1,wherein the fuel tank cap includes a mounting apparatus configured toreceive a fuel additive capsule.
 11. The fuel tank cap of claim 10,wherein the mounting apparatus is positioned on an opposite side of thebottom wall from the internal wall.
 12. The fuel tank cap of claim 5,wherein the apertures are non-adjacent to the side wall.
 13. A fuel tankcap that is removably coupled to a fuel tank of an engine, the fuel tankcap comprising: a fuel cap cover; a housing having a side wall, a bottomwall, and a receptacle; a fuel vapor adsorption material positionedwithin the receptacle; a fuel vapor inlet disposed near the bottom walland configured to provide fluid communication with a fuel tank vaporspace; an outlet disposed near the bottom wall and configured to providefluid communication with the atmosphere; a radially extending internalwall adjacent the bottom wall, the inlet and the outlet being disposedon opposite sides of the internal wall, the internal wall creating afirst region on one side of the internal wall and a second region on theother side of the internal wall; and at least one aperture configured topermit fuel vapor to flow in a fuel vapor flow path from the firstregion to the second region.
 14. The fuel tank cap of claim 13, whereinthe fuel vapor adsorption material includes activated carbon.
 15. Thefuel tank cap of claim 13, wherein the fuel vapor flow path issubstantially circular.
 16. The fuel tank cap of claim 13, wherein theinternal wall is a first internal wall, and wherein the fuel tank capfurther includes at least two additional radially extending internalwalls adjacent the bottom wall and contiguous with the first internalwall.
 17. The fuel tank cap of claim 16, wherein each of at least twoadditional radially extending internal walls has an aperture configuredto permit passage of fuel vapor through the respective internal wall.18. The fuel tank cap of claim 17, wherein the at least two additionalradially extending internal walls includes at least three radiallyextending internal walls, and wherein a combination of the firstinternal wall and the at least three additional radially extendinginternal walls has a substantially X-shaped configuration.
 19. The fueltank cap of claim 17, wherein a combination of the first internal walland the at least two additional radially extending internal walls has asubstantially Y-shaped configuration.
 20. The fuel tank cap of claim 13,wherein the internal wall extends from the bottom wall.
 21. The fueltank cap of claim 13, wherein the inlet is disposed in the bottom wall,and wherein the outlet is disposed in one of the bottom wall and theside wall.
 22. The fuel tank cap of claim 13, wherein the fuel tank capincludes a mounting apparatus configured to receive a fuel additivecapsule.
 23. The fuel tank cap of claim 22, wherein the mountingapparatus is positioned on an opposite side of the bottom wall from theinternal wall.
 24. The fuel tank cap of claim 17, wherein the aperturesare non-adjacent to the side wall.
 25. A fuel tank cap that is removablycoupled to a fuel tank of an engine, the fuel tank cap comprising: ahousing having a bottom wall; a receptacle formed in the housing; aninlet disposed near the bottom wall and configured to provide fluidcommunication with a fuel tank vapor space; an outlet disposed near thebottom wall and configured to provide fluid communication with theatmosphere; a fuel vapor adsorption material positioned within thereceptacle; a radially extending internal wall extending into thereceptacle, the inlet and the outlet being disposed on opposite sides ofthe internal wall; and at least one aperture configured to permit fuelvapor to flow from one side of the internal wall to the other side ofthe internal wall; wherein the internal wall is configured to directfuel vapor through the fuel vapor adsorption material in a substantiallycircular fuel vapor flow path.
 26. The fuel tank cap of claim 25,wherein the fuel vapor adsorption material includes activated carbon.27. The fuel tank cap of claim 25, wherein the internal wall is a firstinternal wall, and wherein the fuel tank cap further includes at leasttwo additional radially extending internal walls extending into thereceptacle and contiguous with the first internal wall.
 28. The fueltank cap of claim 27, wherein each of at least two additional radiallyextending internal walls has an aperture configured to permit passage offuel vapor through the respective internal wall.
 29. The fuel tank capof claim 28, wherein at least two additional radially extending internalwalls includes at least three radially extending internal walls, andwherein a combination of the first internal wall and the at least threeadditional radially extending internal walls has a substantiallyX-shaped configuration.
 30. The fuel tank cap of claim 28, wherein acombination of the first internal wall and the at least two additionalradially extending internal walls has a substantially Y-shapedconfiguration.
 31. The fuel tank cap of claim 25, wherein the fuel tankcap includes a mounting apparatus configured to receive a fuel additivecapsule.
 32. The fuel tank cap of claim 31, wherein the mountingapparatus is positioned on an opposite side of the bottom wall from theinternal wall.
 33. The fuel tank cap of claim 28, wherein the housingincludes a side wall adjacent the bottom wall, and wherein the aperturesare non-adjacent to the side wall.